AJP - Endocrinology and Metabolism, Vol 250, Issue 1 47-E54, Copyright © 1986 by American Physiological Society
Enteral versus parenteral nutrition: comparison of energy metabolism in healthy subjects
O. Vernet, L. Christin, Y. Schutz, E. Danforth Jr and E. Jequier
Continuous respiratory exchange measurements were performed on 10 healthy
young women for 1 h before, 3 h during, and 3 h after either parenteral
(iv) or intragastric (ig) administration of a nutrient mixture (52%
glucose, 18% amino acid, and 30% lipid energy) infused at twice the
postabsorptive resting energy expenditure (REE). REE rose from 0.98 +/-
0.02 (iv) and 0.99 +/- 0.02 kcal/min (ig) postabsorptively to 1.13 +/- 0.03
(iv) and 1.13 +/- 0.02 kcal/min (ig), resulting in nutrient-induced
thermogenesis of 10 +/- 0.6 and 9.3 +/- 0.9%, respectively, when related to
the metabolizable energy. The respiratory quotient rose from preinfusion
values of 0.81 +/- 0.02 (iv) and 0.80 +/- 0.01 (ig) to 0.86 +/- 0.01 (iv)
and 0.85 +/- 0.01 (ig). After nutrient administration the respiratory
quotient fell significantly to below the preinfusion values. Plasma glucose
and insulin concentrations rose during nutrient administration but were
higher during the intravenous route. It is concluded that, although the
response time to intragastric administration was delayed, the thermic
effects and overall substrate oxidations were comparable during intravenous
or intragastric administration, albeit, at lower plasma glucose and insulin
concentrations via the intragastric route.
